The Lockheed C-141 Starlifter & C-5 Galaxy

v1.0.9 / 01 apr 14 / greg goebel / public domain

* Two of the most prominent jet transport aircraft in US military service are
the Lockheed "C-141 Starlifter" and its "big brother", the huge "C-5 Galaxy".
This document provides a history and description of these two aircraft.

* In the 1950s, the US Air Force's Military Air Transport Service (MATS) was
reliant on piston-engined cargolifters, such as the Douglas C-124
Globemaster. By the end of the decade, MATS brass had decided that they
needed a more capable cargolifter, and in the spring of 1960 the USAF issued
a request for proposals under the designation "Specific Operational
Requirement 182 (SOR 182)". SOR 182 specified an aircraft with a cargo
capacity of 27,200 kilograms (60,000 pounds) and a range of 6,480 kilometers
(4,025 miles). Lockheed's proposal was selected, with an initial contract
for five "development, test, and evaluation (DT&E)" aircraft awarded on 13
March 1961. The aircraft was given the designation "C-141 Starlifter".

The Starlifter incorporated ideas from Lockheed's earlier C-130 Hercules
cargolifter, including a high wing; a loading ramp under the high tail;
clamshell rear doors that could be opened in flight for airdrops; and main
landing gear that retracted into fairings alongside the fuselage to ensure an
unobstructed cargo hold. The Starlifter differed from the Hercules in having
wings with a sweepback of 25 degrees and a tee tail, instead of straight
wings and a conventional tail; and four Pratt & Whitney TF33-P-7 turbofans
with 43.2 kN (9,525 kgp / 21,000 lbf) thrust each mounted in pods on
underwing pylons, instead of turboprops mounted on the wing. There were
typically five flight crew.

Initial flight of the Starlifter was on 17 December 1963. The first
production "C-141A" was delivered to the USAF Military Airlift Command (MAC,
successor to MATS) on 23 April 1965. A total of 284 C-141As was built
through February 1968.

Once in service, the Starlifter immediately began daily shuttle flights from
the continental US to Vietnam, carrying 138 passengers in rearward-facing
seats, a configuration that the Air Force decided provided better safety in
crashes; or up to ten standard 463L pallets with a total of 28,880 kilograms
(62,700 pounds) of cargo. It returned with casualties: the aircraft could
carry 80 litters with 23 medical attendants. A few Starlifters were modified
to carry Minuteman ICBMs from the factory to operational bases.

* In practice, MAC found that the Starlifter's cargo hold volume was small
compared to its weight-lifting capability, meaning the aircraft often ran out
of space well before it met its weight limit. To resolve this problem, in
1976 the USAF began a program to "stretch" the Starlifter with fuselage
"plugs" in front of and behind the wing, increasing the length of the
aircraft by 7.11 meters (23 feet 4 inches) and providing space for three more
standard pallets, for a total of 13. The upgrade also involved the addition
of a boom-refueling receptacle behind the cockpit.

The first "YC-141B" conversion performed its initial flight on 24 March 1977.
A total of 270 "C-141B" conversions was performed through June 1982. The Air
Force was very pleased with the conversion program, since it came through
ahead of schedule and under budget, and gave MAC an increased airlift
capacity equivalent to 90 more C-141As.

* Four "NC-141As" that were built as testbeds were not converted to C-141B
standards. One of these, the "L-300" prototype for a commercial Starlifter
that never went into production, was obtained by the US National Aeronautics
& Space Administration (NASA) as a flying astronomical observatory and
designated the "Kuiper Astronomical Observatory (KAO)".

KAO was primarily intended to perform infrared observations of cosmic objects
with a 91 centimeter (36 inch) telescope, mounted to perform observations out
a hole in the fuselage. Such observations must be performed at high
altitude, since the atmosphere absorbs infrared radiation. KAO went into
service in 1974, and obtained many significant astronomical observations.
The flying observatory was retired in 1995, as NASA was beginning work on a
much more sophisticated flying observatory based on the Boeing 747SP jumbo
jetliner, designated the "Stratospheric Observatory for Infrared Astronomy
(SOFIA)". Retiring KAO freed up funds for the SOFIA effort.

* In 1994, the Air Force began a program to refit 13 C-141Bs to the "Special
Operations Low-Level II (SOLL II)" standard, with a total program cost of $41
million USD. These aircraft were operated by the USAF in behalf of the US
Special Operations Command, and included gear for low-level night flying, as
well as defensive countermeasures.

The SOLL designation is a bit confusing; it only defined an operational mode,
SOLL I being daylight low-level operations, and SOLL II being night low-level
operations. In other words, SOLL II only described the aircraft mission, and
did not imply "the second machine in the SOLL series of platforms". The SOLL
II Starlifters were also sometimes referred to as "Special Operations Forces
Improvement Modification (SOFI-Mod)" Starlifters.

The SOLL II Starlifter looked much like any other C-141B, but it could be
recognized by three "knobs" on its chin. One knob was directly under the
nose and was a turret for a Texas Instruments AN/AAQ-17 forward looking
infra-red (FLIR) imager, which gave the aircraft the ability to "see in the
dark". The FLIR imagery was displayed on a CRT at the navigator's station,
and on an auxiliary display for the pilot. The navigator pointed the FLIR
turret using a joystick. The FLIR turret could be removed for maintenance.

The other two knobs were for AN/ALE-40 chaff-flare dispensers, and were
mounted on the "cheeks" of the aircraft. There were also chaff-flare
dispensers in the landing-gear wheel wells and on the wingtips. In addition,
the defensive countermeasures suite included an AN/AAR-44 infrared missile
warning sensor fitted under the fuselage, and an AN/ALR-69 radar warning
receiver with unobtrusive antennas tacked on to the nose and tail.

The defensive countermeasures system could be set to an "automatic" mode to
dispense chaff and flares without crew intervention. The amount of chaff and
flares to be dispensed could be preprogrammed. The sensors also provided an
audible warning to the crew through their headphones, with the crew
dispensing chaff and flares themselves when the system was in "manual" mode.
Even the loadmaster could activate the dispensers, as he or she often kept a
"SAM (surface to air missile) watch" from the rear ramp.

The SOLL II Starlifter also included an enhanced suite of communications
equipment and Global Positioning System (GPS) navigation gear. The
enhancements of the SOLL II increased its weight by about 680 kilograms
(1,500 pounds) compared to a "stock" C-141B. Crews were handpicked for night
operations, which were conducted with night vision goggles (NVGs). All SOLL
II Starlifter cockpit and exterior lighting was NVG-compatible. Additional
crewmembers were included for missions of long duration or with high workload
requirements. Passengers on SOLL II flights tended to find the low-level
flight of the aircraft in pitch darkness, often in formation with another
SOLL II aircraft, to be a little unnerving.

* In the post-Vietnam era, the Starlifter was a major player in airlift
operations to Haiti, Bosnia, Somalia, and Rwanda. It was used very heavily
in the Gulf War in 1991. After the Gulf War, structural problems led to the
imposition of flight restrictions, though these problems were quickly
resolved by a comprehensive repair program. 63 Starlifters were also
upgraded to the "C-141C" standard, with improved avionics, including GPS
navigation gear and digital "glass" cockpits.

However, this update was just to provide a little incremental utility to
stretch the type's service life a bit. The C-141 performed its final flight
for the USAF's Air Mobility Command (AMC), the current incarnation of MATS
and MAC, on 16 September 2004, with two aircraft sent off in a special
ceremony from McGuire AFB in New Jersey to the "boneyard" at Davis-Monthan
AFB in Arizona. Two AF Reserve squadrons continued to operate the type, but
phased it out in the summer of 2006. The very last flight of the C-141C was
on 6 May 2006, when a machine known as the "Hanoi Taxi" -- for its ferry
flights of US prisoners from Hanoi in 1973 -- flew to Wright-Patterson AFB in
Ohio for eventual display at the US Air Force Museum. It had performed
almost 11,000 landings during its career as a C-141A, B, and C.

* In 1963, MATS issued a requirement for a "Cargo Experimental Heavy
Logistics System (CX-HLS)" that specified a heavy long-range cargolifter to
complement the Starlifter. The CX-HLS was to be capable of carrying 56,700
kilograms (125,000 pounds) of cargo over a range of 12,875 kilometers (8,000
miles).

In mid-1964, the USAF issued short-term contracts to Lockheed, Boeing, and
McDonnell-Douglas for design studies of the CX-HLS, as well as to General
Electric and Pratt & Whitney for design studies of new, highly efficient
"high bypass ratio" turbofans to power the aircraft. GE won the engine
competition in August 1963 with what would become the "TF39" turbofan, and
Lockheed won the CX-HLS competition in October 1965 with their "L-500"
design. The first Lockheed "C-5A Galaxy" flew on 30 June 1968. Deliveries
began in 1970. A total of 81 C-5As was built.

The C-5A had the same overall configuration as the C-141, with high wing with
a sweep of 25 degrees, four jet engines in pods on underwing pylons, a rear
loading ramp, a high tee tail, and main landing gear retracting into
fairings. However, it was massively scaled up, with the capability of
lifting two main battle tanks or transporting 345 fully-equipped troops. The
Galaxy was the largest operational aircraft in the world for 15 years, until
it was surpassed by the Soviet Antonov An-124 Condor.

The C-5's nose hinged upward to allow "drive-through" access through the
unobstructed cargo bay, which was pressurized and climate-conditioned. The
dimensions of the hold were as follows:

The upraised nose cleared the cockpit, permitting the aircraft to be taxied
with its nose open. The cockpit was placed at the front of an upper flight
deck on top of the huge cargo hold, and accommodated a typical flight crew of
six. The upper deck also included a 15-person crew-relief compartment with
bunks in front of the wing, and a passenger compartment behind the wing with
73 rearward-facing seats.

The C-5A was powered by four General Electric TF39-GE-1 turbofans with 191.3
kN (19,500 kgp / 43,000 lbf) thrust each. All four engines had thrust
reversers, and it seems the thrust reversers on the inboard engines could
actually be activated while in flight. The aircraft had a four sets of main
gear, each with two-axle bogies with two wheels in front and four in the
rear, and a four-wheel nose gear. The landing gear could "kneel" to assist
in loading cargoes, and featured a system to help land in crosswinds. The
C-5A had a boom refueling capability from the start, as well as a
computerized "Malfunction Detection, Analysis and Recording (MADAR)"
diagnostic system that monitored 800 test points in flight or for ground
servicing.

The C-5A proved its worth in the fall of 1973, in Operation NICKEL GRASS, the
huge airlift to support Israel during the Yom Kippur war, with the big
cargolifter carrying massive quantities of ammunition and weapons to assist
Israeli forces. The Galaxy also performed reliable service in the last years
of the Vietnam War, though one was lost on 4 April 1975 while trying to
evacuate orphans from Saigon. 206 of the 382 people aboard were killed, many
of them infants.

* The C-5A's design specifications had been very aggressive and hard to meet.
The program did not go smoothly, and in fact the program is said to have
coined the term "cost overrun". One of the long-term problems that resulted
was that the aircraft did not live up to its fatigue-life specifications,
with the wings having barely a quarter of the 30,000-hour lifetime specified.
In 1975, Lockheed was awarded a contract to provide new wings to all
surviving aircraft to increase the wing service life to the specified 30,000
hours. The first re-winged aircraft was delivered to the USAF in 1983, with
the re-winging program complete by July 1987.

* In 1982, the Air Force awarded Lockheed a contract for 50 "C-5Bs" that
included the new wing; uprated TF39-GE-1C turbofans; improved alloys and
fasteners; and improved avionics, including a MADAR II diagnostic system,
Bendix weather radar with a color display, and a Delco triple-redundant
inertial navigation system. The crosswind landing system of the C-5A, which
had proven unreliable, was eliminated. Initial flight of the prototype was
on 30 September 1985. Initial deliveries were in 1986 and all deliveries
were completed in 1989.

* Two C-5s were fitted with a countermeasures suite much like that fitted to
the SOLL II Starlifters, under a program designated PACER SNOW. Although
some sources claim there were considerations for fitting the entire C-5 fleet
with PACER SNOW gear, it didn't happen.

Two C-5As were modified for NASA to carry space shuttle payload bay cargoes,
and were given the new designation of "C-5C". They were also known as the
"Space Container Transport System (SCTS)", "Space Container Modifications
(SCM)", "SCM Birds", or "Scum Birds". They were flown by Air Force crews but
were under NASA's operational control, and the USAF had to ask NASA for
permission to use them for non-NASA-related missions. They were also rumored
to be used for ferrying top-secret cargoes to isolated bases for testing, but
of course the government had no comment on such matters. With the end of the
shuttle program, it appears these two machines are being returned to general
Air Force service.

* The Galaxy, or "FRED (Fantastic Ridiculous Economic Disaster)" as it is
known to its crews, has been a valuable asset for US military overseas
deployments for three decades, and served with particular distinction in the
Gulf War, lifting in a little more than two weeks more than the entire Berlin
Airlift in 1949. One was lost in a crash at Ramstein Air Force Base in
Germany on 29 August 1990. The accident was a misfortune, but at least it
was the only loss of a transport during the Gulf War airlift, and only the
fifth Galaxy lost during its entire operational history.

The C-5 has also served in later campaigns, up to and including the US
occupation of Iraq. One was hit by what appears to have been a
shoulder-fired SAM while leaving Baghdad International Airport on 8 January
2004. The transport's number four engine exploded, but the crew managed to
get the machine turned back around and down onto the runway with no
casualties.

* As of 2000, the AMC operated 126 C-5s, including 74 C-5As, 50 C-5Bs, and
two C-5Cs. The C-5s represent an important asset that has a lot of value
left in it. None of the C-5s in operational service are even halfway to
their maximum airframe lives. The FRED had an excellent safety record, but
its reliability left much to be desired, with a poor mission availability
rate.

A set of upgrades have been or are being implemented to keep the C-5 flying.
The initial phase, the $500 million USD "Avionics Modernization Program
(AMP)", began in 1999, with the first C-5 fitted with an AMP upgrade,
consisting of a Honeywell "traffic alert and collision avoidance system
(TCAS)", returned to Air Force service in August 2000. AMP featured
installation of the Honeywell TCAS, with its own dedicated cockpit display.

That led to the much more comprehensive second phase AMP update, in which the
TCAS was an integrated part of the new cockpit system, which features a
digital flight-control system; a state-of-the-art communications and
navigation suite, with satellite links and a GPS receiver; an enhanced ground
proximity warning system; an ARINC-standard data bus; and seven 15 x 20
centimeter (6 x 8 inch) color flat-panel displays, with six for the pilot and
copilot and one for the flight engineer. The new scheme is built around
Honeywell Versatile Integrated Avionics (VIA) processors. The Honeywell
flight-management system permits electronic upload of preprepared flight
plans and can store up to 200 navigation waypoints, compared to 10 in the old
system. According to Lockheed Martin, which implemented the AMP program, all
the new equipment was based on commercially-available products.

The first full AMP upgrade was completed in late 2004, with the last of 79
C-5s upgraded to the spec redelivered in the spring of 2012. The full AMP
upgrade gives the C-5 a flight deck equivalent to a state-of-the-art
commercial airliner and will allow the cargolifter to meet Global Air Traffic
Management standards anywhere in the world.

The third phase is to update AMP machines with new engines under the $7
billion USD "Reliability Enhancement & Reengining Program (RERP)", which is
replacing the current GE TF39 turbofan engines with modern GE CF6-80C2
turbofans. The CF6-80C2 is well-proven, being used on the Boeing 747 and
767, and normally offers 266.9 kN (27,210 kgp / 60,000 lbf) thrust each,
though the engines are derated to 222.4 kN (22,675 kgp / 50,000 lbf) thrust
since the airframe can't handle the additional power. Derating the engines
is not a loss, however, since it improves engine reliability, which is
already very high. Time between overhauls per engine is expected to increase
from 2,000 hours to 10,000 hours. The new engines are also more fuel
efficient, permitting longer flights without stopovers or tanker support.

Lockheed Martin is also implementing this program, with re-engining begun in
2003 and the initial flight of the first re-engined C-5 on 19 June 2006, with
USAF Lieutenant Colonel Todd Markwald in command. After the flight, Markwald
commented: "The aircraft felt like it was made for this engine more so than
for the old ones."

Lockheed Martin chose the GE engine over the Pratt & Whitney PW4650 and the
Rolls-Royce Trent 500. GE will perform off-wing maintenance on the engines
for the USAF. RERP also involves a few structural enhancements to deal with
a new pattern of airframe loads; a new Hamilton Sundstrand auxiliary power
unit (APU); new engine pylons; improvements to the aircraft's antiskid
landing gear and climate-conditioning systems; and, significantly, fit of the
"Large Aircraft Infrared Countermeasures (LAIRCM)" defensive system. LAIRCM
features a missile-warning system and a laser turret to "dazzle" heat-seeking
missiles; it allows the C-5M to operate out of airfields in hot combat zones.
The renewed C-5s, redesignated the "C-5M Super Galaxy", have much improved
performance, with over twice the top payload capacity and a faster climb
rate, and the new engines are significantly quieter as well.

The program has not gone entirely smoothly and the Air Force didn't g1ve the
green light for RERP production until 2009. By early 2014, 16 C-5Ms had been
redelivered, with formal introduction to service at that time. Under the
plan, 12 to 15 C-5s will be upgraded every year. Due to funding cutbacks,
only 52 of the C-5A fleet will be updated to C-5M standard to keep them in
service until at least 2040, with the last refurbished machine to be
delivered in 2017; the rest of the C-5As will be retired.

As a follow-up, Lockheed Martin has investigated enhancements to increase the
fuel efficiency of the C-5, an important consideration in an era of costly
fuel. The enhancements include improved flight surfaces; better
pressurization seals to reduce demand for engine bleed air; streamlining of
defensive countermeasures modules; and possibly 1.8 meter (6 foot) tall
winglets. Fuel savings would be on the order of 3%. There is no commitment
to these fixes at present, but they are clearly attractive. Studies are
already underway for a much more fuel-efficient replacement.

* During the late 1960s and early 1970s, I used to see C-141s coming into
Fairchild Air Force base near Spokane, Washington, on an occasional basis.
Some claim it is an ugly aircraft, but I've always found it somewhat elegant
myself. As far as the C-5 goes, I have a memory of one flying over Spokane
in the same timeframe, with the thing so huge that it appeared to float in
the sky like an airship.

In 1973, when I was stationed at Fort Hood, Texas, I also watched C-5s
swallowing up M-60 tanks as part of the NICKEL GRASS airlift to Israel during
the Yom Kippur War. It is an interesting memory to have observed history in
progress, though the details have largely faded away. As I learned much
later, the load I observed was unusual; tanks were only carried as something
of a test, since the Israelis really needed spares and particularly
ammunition.

* Sources include:

THE ENCYCLOPEDIA OF MODERN WARPLANES, edited by Bill Gunston, Barnes
& Noble, 1995.

Some details on the C-5 were also obtained from a web document by Jason
Hodgkiss, as well as THE AVIATION ZONE website, which is refreshingly
dedicated to "big lifters" instead of the usual assortment of fighters and
bombers more commonly favored on the web.